WikiLeaks Denial of Service (DoS) Attacks...

WikiLeaks was hit by another blow from a denial-of-service attack today. Though the attack initially focused on cablegate.wikileaks.org, the site WikiLeaks is using to host its cache of diplomatic cables;  the attackers eventually moved on to wikileaks.org. Earlier today, WikiLeaks posted a message on its Twitter feed that the attack had exceeded 10 Gigabits per second.

A similar situation arose Nov. 28, just hours before WikiLeaks began posting more than 250,000 U.S. embassy diplomatic cables online. In that case, a Twitter user going by the name th3j35t3r (“Jester”) claimed responsibility for the attack in a tweet, and listed a number of other sites along with the message “TANGO DOWN” to indicate they had been taken down as well. As of publishing, both the wikileaks.org and cablegate.wikileaks.org sites were back online.

Among the cables is a document accusing the Chinese government of directing the Aurora attack that impacted Google, Adobe Systems, Juniper Networks and numerous of other companies. China has denied any involvement in the attack in the past, and has reportedly blocked access to the WikiLeaks site from China since Monday. Another cable discussed the possible implications of a future collapse of North Korea. Hong Lei, a spokesman for China's Foreign Ministry, was quoted as saying at a Beijing news conference on Tuesday. "We hope the U.S. side will handle the relevant issues. As for the content of the documents, we will not comment on that."

Hackers Targeting Black Friday, Cyber Monday.......

Attackers have set their sights on holiday shoppers searching for leaked Black Friday ads, creating malicious sites that appear on search engine result pages, according to a Nov. 18 alert by SonicWall. The security warning comes as shoppers prepare for the 2010 holiday shopping season. Security experts discovered "polluted" results appearing in search engine results for holiday shopping-related terms in advance of Black Friday sales next week. These links take users to a malicious site that tricks users into downloading malware. The terms include "Walmart Black Friday Sales 2010," "Black Friday" and "Cyber Monday". Cyber-criminals view popular search terms as a lucrative target as the terms reflect what people are interested in. In the advent of the holiday shopping season, consumers are searching online for the best deals and discounts, so it goes without question that hackers are "going to try" to take advantage of the holiday traffic.

Criminals create pages that are highly search engine optimized with keywords reflecting currently popular search terms. They also seed keywords and links as comments to boost the malicious pages' search engine rankings. Even if it's for an hour or two, as they will be driving traffic to those pages.

Called SEO poisoning, hackers create these pages that Google and other search engines pick up thinking they are legitimate, and return them when users type in the search terms. Clicking on one of the malicious links redirects the user to another page with embedded JavaScript code that checks the user's Web browser. The next step varies by browser. Users with Internet Explorer are redirected to a fake antivirus landing page claiming the computer is infected by several Trojans. Firefox users are redirected to a fake update page suggesting the user's Flash player is out of date: "Firefox is outdated, also your current version of Flash Player can cause security and stability issues. Please install the free update as soon as possible."
The fake Flash update file downloads the fake antivirus onto the computer and modifies the user registry so that the Trojan runs during system start-up.  It also posts confidential data back to remote servers and redirects the browser to open more pop-up windows.

The infected machines are sending encrypted data back to a specific site and "looks similar" to the InfoStealer Trojan activity. Mac OS X users using Firefox and Internet Explorer will encounter the same malware, and it can be downloaded on to the Mac if they click on those links. However, they are not likely to execute on the Mac.

Varying the malware attack based on the browser the user is using is a common tactic. The attacker is "maximizing the number of potential victims" by "customizing" the behavior to browser-specific vulnerabilities.
The returned search results have titles like "Walmart Black Friday 2010" and the same phrase embedded in the URL string. Since many of the sites are already known to be malicious, Firefox and Google are able to flag the links accordingly. Hackers are also using Best Buy-related search terms, such as "Best Buy Black Friday 2010 deals," to push a fake antivirus software called "Internet Security Suite,".

As the days draw closer to Black Friday, we will certainly see an increase in activity involving these tactics. Spammers and hackers often take advantage of current events, popular trends and holidays such as Halloweento target users. Before Shopping online, make sure that your operating system, browser and security software are up-to-date and enable secure browsing on the Web browser before going to unknown sites.

Defeating Drive-by Downloads in Windows

The Problem

Drive-by Downloads have been a problem for a number of years now. This avenue of attack has become more popular as attackers have developed more techniques to direct visitors to their exploit websites. The three most common scenarios are: Search Engine poisoning, malicious forum posts, and malicious flash ads. These are complex, multi-step attacks that build upon each other to eventually install some sort of malware on the victim's machine. I call this series of steps the "Chain of Compromise" (I've also heard this described as the kill-chain.) It's our job as the defense to break that chain as early as possible. If we allow it to complete, then we have a real incident on our hands.

Countermeasures

There are a number of system countermeasures that you could use to defeat drive-by attacks. I've got an incomplete list below comparing their average cost to install, both monetarily and a vague measure of the amount of technical effort required.

Countermeasure	Cost	Tinker-Factor
Anti-Virus	Free to $80 USD	Low
Web-filter	Free to Thounsands	Medium to High
Alternative Browser	Free	Low to Medium
No-script	Free	Medium
Adblocker	Free	Low
Flashblock	Free	Low
OpenDNS	Free	Medium
Alternative Document Viewer	Free	Low to Medium
Executable Whitelist	Free to Hundreds	High
Full-proxied Environment	Hundreds to Thousands	Medium to High
IPS	Free to Thousands	Medium to High
Disable Administrator rights	Free	Low to Medium
Masqurade User-Agent	Free	Low
DEP/ASLR	Free	Low to Medium

• Anti-Virus: not much to say about this, everyone has it now, and it's the countermeasure that gets the most attention by attackers. It's easily evaded with minimal effort.
• Web-filter: this could be on the system itself, or injected through a web proxy. Free options include K9
• Alternative Browser: something other than IE or Firefox. By moving to a less-popular browser you stepping out of the line of fire in most cases. At least is reduces your attack surface to your office/document viewers (e.g. Flash, Acrobat, etc.)
• No-script: allows you to block execution of javascript on new/unknown sites.
• Adblocker: typically used to avoid annoying advertisements, a bit controvertial since websites are supported by their ad revenue, but more often becoming a necessity due to poor quality-control/security-measures by ad-servers.
• Flashblock: like no-script, but for flash. Allows you to run flash when you need it, and block it from unknown/unexpected sources.
• OpenDNS: if you use OpenDNS for your domain name resolution, it can block requests to suspicious/malicious destinations.
• Alternative Document Viewer: use an alternative PDF viewer to avoid a number of Adobe Acrobat vulnerabilities and avoid executing unnecessary code. You'll likely lose the ability to use interactive PDF forms, but you could always keep a copy of Acrobat Reader handy for the few times you need it.
• Executable Whitelist: this is ideal defense against unknown code executing on your system. It's also extremely difficult to maintain over time.
• Full-proxied Environment: don't let your systems have direct access to the Internet. Proxy all out-bound requests. This is extremely effective against most backdoors and infected systems reaching out to command and control servers via something other than HTTP/HTTPS (those ofen hijack the browser for this purpose and thus inherit the proxy settings.)
• IPS: Either a host-based or network-based IPS system capable of blocking known exploits.
• Disable Administrator Rights: is the victim account is not running as administrator some of the follow-on damage from a compromise can be limited. However, this does not prevent the compromise in most cases.
• Masquerade User-Agent: some browsers and some add-ins allow you to alter the user-agent and other identifying information to thwart targeted attacks.
• DEP/ASLR: Data Execution Prevention or Address Space Layout Randomization helps protect Internet Explorer from certain classes of exploits at the cost of some functionality.

Now we'll see how these countermeasures stack up against the attackers in a few scenarios.

Scenario 1: Search Engine Poisoning

In our first scenario, the attackers have set up a network of compromised websites that redirect the visitor to one of their exploit servers. The exploit server has some javascript on it that effectively scans the potential victim for the versions of the browser, java, flash, and PDF client. Based on the results of the scan and the geo-location of the victim's IP address the exploit server launches a targeted attack against any vulnerable browser, java, flash or PDF client on the system. If this attack is successful, the victims machine will download a payload from their payload server. This is exploit-as-a-service, where this criminal group offers the delivery of another criminal group's payload to a certain number of IP addresses in a certain geographical region. This is how they make their money: they build an maintain the infrastructure of redirect servers, exploit servers, and download servers, this infrastructure is then rented out to other groups. In addition to building the infrastructure, they also spend a lot of time promoting their redirect sites in common search engines.
So, in our scenario, our victim goes to their favorite search engine looking for "holiday cookie recipes" and in their search results are a number of links that lead to one of our attacker's redirect sites. Let's say the victim queues up a number of requests in their browser tabs.

1. The browser will open up a connection to one of the redirect sites, it will have a meta-refresh, or iframe, or return a 302 to direct the user to the exploit site.
2. The exploit-site delivers a set of javascript routines to the browser.
3. These routines identify version information for: the browser, java, flash and PDF reader.
4. The exploit server returns the exploit that is most likely to succeed.
5. The victim's application is exploited and commanded to pull down and execute the downloader code (either from the exploit site itself, or the downloader site)
6. The downloader code is executed on the system, this downloads additional payload and executes this on the victim's system.
7. Victim's system now needs to be re-imaged.

Use this table below to map out which countermeasures are effective at which stage in the attack. Keep in mind that the earlier you break the chain, the better it is for your environment. Compare this to the costs above and see if you can identify the best defense strategy for this scenario.
 Key: "-" denotes no impact, Potential means that under the best conditions the countermeasure is effective, Likely means it's effective more often, and Complete is near-certain that it works.

	Redirect Site	Exploit Site	Java-script Recon	Browser Exploit	Flash Exploit	PDF Exploit	Download Site	Downloader code	Secondary Payload	Command and Control Established
Anti-Virus	-	-	-	-	-	-	-	Potential	Potential	-
Web-filter	Potential	Potential	-	-	-	-	Potential	-	-	Potential
Alternative Browser	-	-	-	Likely	-	-	-	-	-	-
No-script	-	-	Complete	-	-	-	-	-	-	-
Adblocker	-	-	-	-	-	-	-	-	-	-
Flashblock	-	-	-	-	Complete	-	-	-	-	-
OpenDNS	Potential	Potential	-	-	-	-	Potential	-	-	Potential
Alternative Document Viewer	-	-	-	-	-	Potential	-	-	-	-
Executable Whitelist	-	-	-	-	-	-	-	Complete	Complete	-
Full-proxied Environment	-	-	-	-	-	-	-	-	-	Likely
IPS	-	-	Possible	Likely	Possible	Possible	-	Possible	Possible	Possible
Disable Administrator rights	-	-	-	-	-	-	-	-	-	-
Masquerade User-Agent	-	-	-	Possible	-	-	-	-	-	-
DEP/ASLR	-	-	-	Possible	-	-	-	-	-	-

Scenario 2: Malicious Forum Post

In our second scenario, our same attacker group is hosting an exploit infrastructure and getting paid to install malicious payloads. Instead of using search engine poisoning and redirect sites, they are exploiting vulnerabilities in common forum software to inject iframes into forum posts. Here our victim is reading up on solutions to a pesky automobile problem, and is search internet forums for advice. They happen upon a thread that one of the attackers has placed a malicious comment. This kicks off the series of events very similar to Scenario 1.

	Forum iframe	Exploit Site	Java-script Recon	Browser Exploit	Flash Exploit	PDF Exploit	Download Site	Downloader code	Secondary Payload	Command and Control Established
Anti-Virus	-	-	-	-	-	-	-	Potential	Potential	-
Web-filter	-	Potential	-	-	-	-	Potential	-	-	Potential
Alternative Browser	-	-	-	Likely	-	-	-	-	-	-
No-script	-	-	Complete	-	-	-	-	-	-	-
Adblocker	-	-	-	-	-	-	-	-	-	-
Flashblock	-	-	-	-	Complete	-	-	-	-	-
OpenDNS	--	Potential	--	-	-	-	Potential	-	-	Potential
Alternative Document Viewer	-	-	-	-	-	Potential	-	-	-	-
Executable Whitelist	-	-	-	-	-	-	-	Complete	Complete	-
Full-proxied Environment	-	-	-	-	-	-	-	-	-	Likely
IPS	-	-	Possible	Likely	Possible	Possible	-	Possible	Possible	Possible
Disable Administrator rights	-	-	-	-	-	-	-	-	-	-
Masquerade User-Agent	-	-	-	Possible	-	-	-	-	-	-
DEP/ASLR	-	-	-	Possible	-	-	-	-	-	-

There's really not much different in this table, so an effective strategy targeting malicious search engine results is similarly effective against malicious forum posts

Scenario 3: Malicious Flash Ad

Much like the above two scenarios, but this one differs in how the victim reaches the exploit. In this case, during their lunch hour they browse over to their favorite news website. It's in your company's web-proxy whitelist because it's a "trusted site." Unfortunately, that website's advertisement broker didn't detect the redirect code hidden in the flash ad, so now your victim, who didn't click on the advertisement, is silently redirected to the exploit site.

	Visit Exploited News Site	View Malicious Ad	Exploit Site	Java-script Recon	Browser Exploit	Flash Exploit	PDF Exploit	Download Site	Downloader code	Secondary Payload	Command and Control Established
Anti-Virus	-	-	-	-	-	-	-	-	Potential	Potential	-
Web-filter	-	Potential	Potential	-	-	-	-	Potential	-	-	Potential
Alternative Browser	-	-	-	-	Likely	-	-	-	-	-	-
No-script	-	-	-	Complete	-	-	-	-	-	-	-
Adblocker	-	Likely	-	-	-	-	-	-	-	-	-
Flashblock	-	Complete	-	-	-	Complete	-	-	-	-	-
OpenDNS	-	Potential	Potential	-	-	-	-	Potential	-	-	Potential
Alternative Document Viewer	-	-	-	-	-	-	Potential	-	-	-	-
Executable Whitelist	-	-	-	-	-	-	-	-	Complete	Complete	-
Full-proxied Environment	-	-	-	-	-	-	-	-	-	-	Likely
IPS	-	-	-	Possible	Likely	Possible	Possible	-	Possible	Possible	Possible
Disable Administrator rights	-	-	-	-	-	-	-	-	-	-	-
Masquerade User-Agent	-	-	-	-	Possible	-	-	-	-	-	-
DEP/ASLR	-	-	-	-	Possible	-	-	-	-	-	-

Example Strategies

My home computer was compromised about a week ago by a FakeAV program. I was running an up-to-date patched version of Windows 7 running Internet Explorer and anti-virus. So, basically I really didn't stand a chance. The default strategy of: move to firefox, install no-script etc...wasn't a viable option at the time. My option was to focus more on OpenDNS and K9 to help from getting redirected to known malicious websites to begin with. Yes, that machine is likely to get popped again but it's a bit less likely.

If you look at the tables above, you'll note that the average user running Internet Explorer, Shockwave, and Acrobat Reader relying only on Anti-virus doesn't stand much of a chance. On the other end of the spectrum, an environment that relies only upon Executable Whitelist will certainly break the compromise chain, but very late within the event and at a likely-large cost of effort. When giving advice on which browser to use, I often recommend, firefox since it can support addons like adblock, flashblock, and no-script. When we make such recommendations it never fails that someone will complain how their environment and circumstances are different. This is the primary motivator behind the capabilities-matrix approach. You can evaluate what countermeasures are appropriate/affordable/possible in your situation and perhaps help determine if the payoff of a countermeasure is worth the investment.

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